Effect of phosphorus/nitrogen/carbon component ratio in aqueous flame retardant on the fire prevention of wood substrate

Herein, various of aqueous halogen-free flame retardants (FRs) were fabricated by controlling the weight ratio of phosphorus/nitrogen/carbon compounds. The prepared FRs showed good dispersion level at ambient conditions and easily adhering feature on the wood substrate. Owing to the synergistic flame-retardant effect of phosphorus/nitrogen/carbon compounds on wood, the FR1 coated wood (W-FR1) could form non-pores, compact, and continuous phospho-carbonaceous layer under fire. Meanwhile, W-FR1 exhibited a higher LOI (59.5%) and UL-94 rating (V-0). Moreover, the ignition time of W-FR1 was significantly delayed from 35 to 570 s. Additionally, W-FR1 showed 31.6% and 47.1% reductions in THR and TSP, respectively, 99.3% increment in char residue, as compared to the untreated wood. The present research offers a promising aqueous flame retardant for potential forest fire prevention.